Pallet formed from molded fibrous panel material

ABSTRACT

A pallet is constructed of a molded fibrous panel material comprising a sheet portion defining opposite planar surfaces, and a grid of intersecting ribs projecting from one of the planar surfaces of the sheet portion, the sheet portion and ribs being integrally molded from fibrous material. The pallet comprises a horizontal portion of the molded fibrous panel material forming an upper support surface of the pallet, and at least two spaced runners joined to the horizontal portion for engaging the ground to space the horizontal portion above the ground. Each runner comprises at least two vertical portions of the molded fibrous panel material arranged in parallel relation and bonded to one another. In one embodiment, a single panel member is folded along a series of parallel fold lines extending across a width of the member, so as to form the runners and the horizontal portion from the single member.

FIELD OF THE INVENTION

The invention relates to pallets for supporting items during shipmentand storage. In particular, the invention relates to a pallet formedpredominately from fibrous material.

BACKGROUND OF THE INVENTION

Pallets traditionally have been manufactured of wood. The drawbacksassociated with wooden pallets are well known, as noted for example inU.S. Pat. No. 5,184,558, incorporated herein by reference. Briefly, suchdrawbacks include heaviness, which makes the pallets cumbersome tohandle and costly to ship, relatively great expense because of thecostliness of wood, and difficulty and expense of disposing of thepallets when their useful life has been expended.

Because of such problems, various types of non-wooden pallets have beenproposed. Some of these pallets are based on corrugated paperboardmaterials; others are based on honeycomb sandwich types of sheetmaterials. Still others are one-piece structures molded from fibrousmaterial.

Pallets based on corrugated paperboard materials suffer from relativelypoor rigidity because corrugated paperboard material by its nature isweak in bending parallel to the running direction of the flutes.Attempts have been made to improve rigidity in all directions by forminglaminations of multiple layers of corrugated paperboard with the flutesin successive layers being oriented orthogonally. There is thus a needfor a substantial number of separate pieces of corrugated sheetmaterial, each die cut to appropriate size and shape, the pieces thenbeing glued together. Thus, production and assembly of a pallet fromsuch materials is relatively complex and expensive.

Pallets formed from honeycomb sandwich materials likewise tend toconsist of a substantial number of separate pieces, and hence arerelatively complex and expensive to produce and assemble. Additionally,the bond between the honeycomb cells and the face sheets represents aweak link in honeycomb sandwich structures; if this bond should break,the structure loses a great deal of its bending stiffness. In honeycombsandwich panels based on paper, furthermore, exposure of the panels towater or other liquids can substantially weaken the panels.

With regard to one-piece molded fibrous pallets, a significant drawbackis the need for a differently configured mold for each different palletsize or configuration to be produced.

SUMMARY OF THE INVENTION

The invention addresses the above needs and achieves other advantages,by providing a pallet formed of molded fibrous panel material of aspecial type having substantial strength and relatively light weight.The pallet can be constructed from a small number of separate pieces ofthe panel material, or even from a single piece of the panel material.

More particularly, in accordance with the invention, a pallet isconstructed of a molded fibrous panel material comprising a sheetportion defining opposite planar surfaces, and a grid of intersectingribs projecting from one of the planar surfaces of the sheet portion,the sheet portion and ribs being integrally molded in one piece fromfibrous material. The fibrous material can be, for example, recycledpaper fibers. If water-resistance is required, the molded fibrous panelmaterial can be impregnated with a suitable resin. The panel hassubstantial rigidity and integrity by virtue of its one-piececonstruction and the grid of intersecting ribs.

A pallet in accordance with the invention comprises a horizontal portionof the molded fibrous panel material forming an upper support surface ofthe pallet, and at least two spaced runners joined to and extendingdownward from the horizontal portion for engaging the ground to spacethe horizontal portion above the ground. Each runner comprises at leasttwo vertical portions of the molded fibrous panel material arranged inparallel relation and bonded to one another.

In one embodiment, a single panel member is folded along a series ofparallel fold lines extending across a width of the member, so as toform the runners and the horizontal portion from the single member.Because of the substantial rigidity of the panel, the grooves are formedin the panel to create the fold lines. The grooves represent regions inwhich fibrous material that would otherwise be there is missing orremoved. The grooves preferably are generally V-shaped with a 90-degreeincluded angle between opposite side walls of the grooves so that thepanel can be folded 90 degrees about the fold line. The grooves eithercan be molded into the panel when it is molded, or alternatively can beformed by mechanically removing material (e.g., by routing) from thepanel after it is formed.

In another embodiment, a top panel is affixed atop the horizontalportion of the pallet, such as by gluing. The top panel gives addedstrength to the pallet and also presents a smooth top surface. The toppanel in one embodiment comprises a laminated multi-layer sheet, forexample formed from paperboard sheets. Alternatively, the top panel canbe another piece of the molded fibrous panel material, with the ribsfacing downward toward the horizontal portion of the pallet. The ribs ofthe top panel can be bonded to the ribs of the horizontal portion,optionally with an intervening piece of sheet material (e.g., paperboardor the like) disposed therebetween.

The molded fibrous panel material forming the horizontal and verticalportions of the pallet can comprise a single layer of the molded fibrouspanel material, such that one side of the panel is planar and the otherside has exposed ribs. Alternatively, the panel material can comprise adouble layer wherein the two layers are joined rib-to-rib, for addedrigidity.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

Having thus described the invention in general terms, reference will nowbe made to the accompanying drawings, which are not necessarily drawn toscale, and wherein:

FIG. 1 is a perspective view of a piece of molded fibrous panel materialused for constructing pallets in accordance with the invention;

FIG. 2 is a cross-sectional view taken along line 2-2 in FIG. 1;

FIG. 3 is a pallet in accordance with a first embodiment of theinvention;

FIG. 4A shows a portion of a molded fibrous panel, illustrating a seriesof parallel fold lines defined as V-shaped grooves in the panel;

FIG. 4B shows the panel after being folded 90 degrees along one of thefold lines;

FIG. 5 shows a portion of the panel of FIG. 3, depicting a runner ingreater detail;

FIG. 6 illustrates an alternative embodiment of the invention;

FIG. 7 shows another embodiment of the invention;

FIG. 8 depicts a further embodiment of the invention;

FIG. 9 shows a still further embodiment of the invention; and

FIG. 10 shows yet another embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present inventions now will be described more fully hereinafter withreference to the accompanying drawings, in which some, but not allembodiments of the invention are shown. Indeed, these inventions may beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein; rather, these embodiments areprovided so that this disclosure will satisfy applicable legalrequirements. Like numbers refer to like elements throughout.

FIGS. 1 and 2 show a molded fibrous panel 20 that is used forconstructing pallets in accordance with the invention. The panel 20 canbe formed by a process generally similar to that disclosed in U.S. Pat.No. 4,702,870 to Setterholm et al., incorporated herein by reference, orby a process such as described in co-pending U.S. patent applicationSer. No. ______, filed on Dec. 5, 2003, entitled “Apparatus and Processfor Forming Three-Dimensional Fibrous Panels” incorporated herein byreference. The process produces a three-dimensional panel that has asheet portion 22 defining opposite planar surfaces 24 and 26, and a gridof intersecting ribs 28 projecting from one surface 24 of the sheetportion. To make the panel, an aqueous fiber stock is deposited into amold comprising a porous support plate or screen on which are affixed aplurality of resilient elastomeric mold pieces or projections oftruncated conical or pyramidal shape. The mold pieces are spaced aparton the porous support plate so that intersecting channels are definedbetween the mold pieces. The aqueous stock fills the mold to a depthgreater than the height of the mold pieces, so the stock covers theupper surfaces of the mold pieces. A flat mold plate is urged againstthe stock and presses the stock down into the mold; the stock isdewatered through openings in the porous support plate. The pressuredewaters and densifies the panel, and the wet panel is then dried fullyto complete the process.

The panel 20 advantageously can have a thickness ranging from about¼-inch to about ¾-inch or more. The panel can be formed from recycledpaper fibers. The panel can be impregnated with a resin to render itwater-resistant, if desired. An advantage of the panel over the priorart is its relatively large strength-to-weight ratio, which makespossible the construction of pallets of relatively light weight butsubstantial strength.

FIG. 3 depicts a pallet 30 in accordance with a first embodiment of theinvention. The pallet 30 is constructed from a single molded fibrouspanel 20 and a top panel 50. The molded fibrous panel 20 is rectangularin shape. The panel 20 is folded along a series of parallel fold linesto form three runners 32, 34, 36 spaced apart and parallel to oneanother, as further described below. The top panel 50 is then bonded tothe folded panel 20 by gluing or the like.

The formation of the runner 32 is depicted in FIGS. 4A, 4B, and 5; theother runners are formed in a similar fashion. The panel 20 is providedwith a series of spaced, parallel fold lines A, B, C, D, E, F, G, H, I,J (FIG. 3); the fold lines A, B, and C are used for forming the firstrunner 32. The fold line A is spaced from one edge of the panel 20 by adistance corresponding to a desired vertical extent of the runner 32;panel section 20 a is defined between the panel edge and the fold lineA. The fold line B is spaced from the fold line A by a minimum distanceroughly equal to 1.5 to 2 times the thickness of the panel; panelsection 20 b is defined between fold lines A and B. The fold line C isspaced from the fold line B by a distance approximately equal to thevertical height of the runner minus the thickness of the panel 20; panelsection 20 c is defined between the fold lines B and C, and a panelsection 20 d is connected to the panel section 20 c at the fold line C.

Because the panel 20 has substantial bending stiffness as a result ofthe ribs 28, it is not possible to fold the panel without substantialbreakage of fibers and buckling of the panel along the fold, andaccordingly it is necessary to provide a groove or channel along each ofthe desired lines about which the panel is to be folded, as shown inFIG. 4A. In the region of each groove, the ribs are substantiallyremoved or interrupted so that the remaining material, at least at thebottom of the groove, consists substantially entirely of the sheetportion 22 of the panel. A preferred configuration of the grooves isdepicted in FIG. 4A. Each groove preferably is V-shaped; the oppositeside walls of the groove preferably define an angle of substantially 90degrees therebetween. Accordingly, when the panel is folded 90 degreesabout the fold line, the opposite side walls of the groove come intosubstantially abutting relation and can be glued together to secure thepanel in the folded position.

The V-shaped grooves can be formed in various ways. In one embodiment,the grooves are formed during the molding process, by suitablyconfiguring the mold. Alternatively, the panel can be molded withoutgrooves, and then the panel can be routed, machined, or otherwisemechanically operated upon to remove material to form the grooves.

To form the runner 32, the panel sections 20 a and 20 b are folded as aunit 90 degrees clockwise about the fold line B as shown in FIG. 4B,then the panel section 20 a is folded relative to panel section 20 b 90degrees clockwise about the fold line A. At this point, the panelsections 20 a and 20 c are parallel to each other and are rib-to-rib.These panel sections are glued together to form the runner 32. Therunner is then folded 90 degrees counterclockwise about the fold line C,with the resulting structure being shown in FIG. 5. Panel section 20 dforms a horizontal portion of the pallet on which a load will besupported. The other runners 34 and 36 and further horizontal portionsare similarly formed by folding the panel about the respective foldlines D-J. Finally, the top panel 50 is attached atop the panel 20 bygluing or the like to complete the pallet construction. Although aparticular order of folding the panel 20 about the fold lines has beendescribed, it will be recognized that the order may be different whilearriving at the same end result.

FIG. 6 illustrates a portion of a pallet 30′ in accordance with a secondembodiment of the invention. This pallet is essentially the same as thepallet 30 described above, except that the panel 20 is reinforced in theregion of the fold lines A and B by a reinforcing web 52. Thereinforcing web 52 is employed to prevent or minimize fiber breakage inthe region of the fold lines that may otherwise result upon folding ofthe panel. The reinforcing web may be an adhesive tape such as apressure-sensitive adhesive tape comprising a substrate of paper orcloth having a layer of pressure-sensitive adhesive thereon. Thereinforcing web preferably is affixed to the panel prior to folding.

A third embodiment of the invention is depicted in FIG. 7. The pallet130 shown in FIG. 7 is generally similar to the pallet 30 previouslydescribed, except as noted herein. The pallet 130 has a panel 20 foldedalong fold lines A, B, C, etc., so as to form runners 32, etc., aspreviously described, and a top panel 50 affixed atop the panel 20.However, in the present embodiment, the runners are reinforced withadditional stiffening members. Thus, the runner 32 is shown having astiffening member 60 disposed between the panel portion 20 a and thepanel portion 20 c that make up the runner. The stiffening member isbonded to the panel portions 20 a and 20 c with adhesive or the like. Toprovide the necessary space between the panel portions to accommodatethe thickness of the stiffening member 60, the fold lines A and B arespaced slightly farther apart than in the previously described pallet30, so that when the panel portions 20 a and 20 c are parallel to eachother there is a space between them substantially equal to the thicknessof the stiffening member 60. The stiffening member 60 can comprisevarious materials, including but not limited to metal, wood, hardplastic, hard rubber, fiber-reinforced plastic, multi-layer paperboardlaminations, and the like.

FIG. 8 shows a fourth embodiment of the invention. The pallet 230 ofFIG. 8 is generally similar to the pallet 30 described above, exceptthat the top panel 250 comprises a fibrous molded panel of the typeshown in FIG. 1. Thus, the top panel 250 has a sheet portion 252 andribs 258 projecting therefrom. The top panel 250 is bonded to the panel20 that forms the runners of the pallet. Preferably, the panel 20 hasits ribs 28 projecting upwardly and the top panel 250 has its ribs 258projecting downwardly, and the two panels are bonded rib-to-rib.Optionally, there can be an intervening sheet 260 of paper or othermaterial disposed between and bonded to the two panels.

A fifth embodiment of the invention is illustrated in FIG. 9. The pallet330 of FIG. 9 is constructed in a fashion similar to that used forconstructing the pallet 30, except that the starting panel 320 used forforming the runners is a double-layer panel having two panels of thetype illustrated in FIG. 1, bonded rib-to-rib (with or without anintervening sheet therebetween). Thus, both opposite surfaces of thepanel 320 are smooth and planar. The panel is provided with groovesalong the desired fold lines by routing or the like, as previouslydescribed, and is folded to form the runners 332, etc., and thehorizontal portions 320 d, etc. However, in the pallet 330, since thehorizontal portions of the panel 320 already comprise a double-layer ofpanel material, there is no need for an additional top panel. Thus, theentire pallet is formed from one double-layer panel. As with theembodiment of FIG. 7, the runners can be further strengthened, ifdesired, by stiffening members.

Finally, a sixth embodiment of the invention is shown in FIG. 10. Thepallet 430 of FIG. 10 is formed differently from the previouslydescribed pallets, with respect to the formation of the runners. In thisembodiment, each runner, such as the runner 432 shown in the drawing, isformed by bonding together two or more separate and discrete pieces ofpanel material, and is then bonded to a top panel of the pallet. Thus,as shown, the runner 432 comprises two double-layer pieces of panelmaterial 440 and 442 bonded together. The piece 440 comprises two panels440 a and 440 b bonded together rib-to-rib (with or without anintervening sheet therebetween); likewise, the piece 442 comprises twopanels 442 a and 442 b bonded together rib-to-rib (with or without anintervening sheet therebetween). The pallet 430 includes a top panel 450comprising a double-layer piece of panel material having two panelsbonded together rib-to-rib (with or without an intervening sheettherebetween). Alternatively, the top panel could be a single layer ofthe panel material, or could be another type of construction such as amulti-layer paperboard lamination. The runners could be formed of fewerthan four layers of the panel material; for example, the runners couldcomprise two layers of the panel material. The runners could includestiffening members as previously described.

Many modifications and other embodiments of the inventions set forthherein will come to mind to one skilled in the art to which theseinventions pertain having the benefit of the teachings presented in theforegoing descriptions and the associated drawings. Therefore, it is tobe understood that the inventions are not to be limited to the specificembodiments disclosed and that modifications and other embodiments areintended to be included within the scope of the appended claims.Although specific terms are employed herein, they are used in a genericand descriptive sense only and not for purposes of limitation.

1. A pallet formed predominately of molded fibrous material, comprising:a molded fibrous panel material comprising a sheet portion definingopposite planar surfaces, and a grid of intersecting ribs projectingfrom one of the planar surfaces of the sheet portion, the sheet portionand ribs being integrally molded in one piece from fibrous material; ahorizontal portion of said molded fibrous panel material forming anupper support surface of the pallet; the pallet further comprising atleast two spaced runners joined to and extending downward from thehorizontal portion for engaging the ground to space the horizontalportion above the ground, each runner comprising at least two verticalportions of the molded fibrous panel material arranged in parallelrelation and bonded to one another.
 2. The pallet of claim 1, whereineach runner includes a separate stiffening member disposed between andbonded to two of the vertical portions.
 3. The pallet of claim 1,wherein the horizontal portion and the vertical portions are allintegrally and serially joined together along a series of spacedparallel fold lines in the molded fibrous panel material.
 4. The palletof claim 3, wherein each fold line comprises a groove in the moldedfibrous panel material.
 5. The pallet of claim 4, wherein the groovesare molded into the molded fibrous panel material.
 6. The pallet ofclaim 4, wherein the grooves are formed by mechanically removing fibrousmaterial from the molded fibrous panel material.
 7. The pallet of claim4, wherein at least some of the grooves are generally V-shaped with anincluded angle of about 90 degrees between opposite side walls of thegroove.
 8. The pallet of claim 1, further comprising a top panel affixedatop the horizontal portion.
 9. The pallet of claim 8, wherein the toppanel comprises a multi-ply laminated material.
 10. The pallet of claim9, wherein the laminated material comprises paperboard.
 11. The palletof claim 8, wherein the top panel comprises another piece of the moldedfibrous panel material.
 12. The pallet of claim 11, wherein the ribs ofthe top panel face downward and the ribs of the horizontal portion faceupward to oppose the ribs of the top panel.
 13. The pallet of claim 12,wherein the ribs of the top panel are bonded directly to the ribs of thehorizontal portion.
 14. The pallet of claim 12, wherein the ribs of thetop panel are joined to the ribs of the horizontal portion via anintervening piece of sheet material disposed therebetween, said sheetmaterial being bonded to the ribs of the top panel and horizontalportion.
 15. The pallet of claim 3, wherein the molded fibrous panelmaterial forming the horizontal and vertical portions comprises a singlelayer of the molded fibrous panel material.
 16. The pallet of claim 3,molded fibrous panel material forming the horizontal and verticalportions comprises two layers of the molded fibrous panel materialjoined rib-to-rib.
 17. The pallet of claim 3, further comprising areinforcing web bonded to one side of the molded fibrous panel materialalong at least one of the fold lines.
 18. The pallet of claim 17,wherein the reinforcing web comprises a pressure-sensitive adhesivetape.
 19. The pallet of claim 3, wherein the molded fibrous panelmaterial has, in order, from one end to an opposite end of the moldedfibrous panel material: first, second, and third fold lines for forminga first runner; fourth, fifth, sixth, and seventh fold lines for forminga second runner; and eighth, ninth, and tenth fold lines for forming athird runner.
 20. The pallet of claim 1, wherein the molded fibrouspanel material is formed from recycled paper fibers.
 21. The pallet ofclaim 20, wherein the molded fibrous panel material is impregnated witha resin for rendering the molded fibrous panel material substantiallywater-resistant.
 22. The pallet of claim 1, wherein each runnercomprises a first pair of layers of the molded fibrous panel materialjoined rib-to-rib.
 23. The pallet of claim 22, wherein each runnercomprises a second pair of layers of the molded fibrous panel materialjoined rib-to-rib and joined to the first pair such that the runnercomprises four layers.
 24. The pallet of claim 22, wherein thehorizontal portion comprises a separate piece of the molded fibrouspanel material joined to the runners.